In modern engineering, molded-case circuit breakers are known and are widely used. Molded-case circuit breakers of this type enable, in particular, the switching of high currents or powers, for example currents of 70 kA or higher. In this case, molded-case circuit breakers of this type are often also designed with safety devices, for instance an overload and/or short-circuit protection device and corresponding trip switches. Thus, known molded-case circuit breakers also increase safety when switching such currents.
In this case, it is a requirement on such molded-case circuit breakers that the externally visible parts of the molded-case circuit breaker correctly indicate the internal switching state of the molded-case circuit breaker at all times in a manner visible to a user. In particular, it is an essential requirement that the molded-case circuit breaker does not indicate the interruption of a flow of current if, internally the flow of current is not interrupted, for example owing to melting of the contacts owing to an overvoltage and/or an overload. In the case of known molded-case circuit breakers, this is achieved, for example, by a handle of the molded-case circuit breaker at least not being able to be locked in an “OFF” position as soon as such a serious fault state is present.